Synergistic effect of APOE genotype and obesity in CNS inflammation and risk of Alzheimer's disease

项目摘要 我们以前曾探讨过这样的假设，即APOE基因型改变了正常的脑神经化学， 在生命的早期，大脑的结构，产生一个环境，改变老年痴呆症（AD）的风险。 对APOE基因敲入小鼠的研究表明，APOE基因型影响神经炎症， 以同种型特异性方式对各种神经损伤的反应，apoE 4显示最少的抗- 炎症活动。炎症也是AD的几种环境风险因素的结果，例如 创伤性脑损伤、肥胖和代谢综合征。肥胖是最强的环境风险因素， AD. 14%的美国人口是APOE 4携带者，35%的人口患有肥胖症， 了解这两种常见的AD风险因素如何协同作用非常重要。性也是一个关键的 认知障碍的风险可变，女性的风险明显更高。因此，AD的风险取决于 基因、环境和性别效应之间的一系列复杂联系。该项目旨在分析 在健康啮齿动物模型中的这些相互作用，从而提供可用作标记的早期疾病靶点。 AD风险和疾病干预的目标。目的1将确定神经炎症的强有力的标志物， APOE 3和APOE 4雄性和雌性小鼠在经历饮食诱导的慢性外周炎症后。 我们将验证我们的假设，即特定的神经炎症通路将受到以下因素的协同影响： 这三个风险因素。我们已经开始通过非定向的 转录分析，我们将通过qPCR测试这些发现的严谨性。我们将进一步细化具体 使用免疫荧光、原位杂交分析和激酶测量来研究神经炎性通路。 最后，我们将通过定义炎症细胞的密度、形态和运动性来定义炎症细胞反应。 使用我们的CX 3CR 1GFP/+小鼠模型在APOE 3和APOE 4敲入背景下观察小胶质细胞。目标2将 确定两种安全的抗炎药物对以下亚组中CNS炎症标志物的影响： 受影响最大的APOE雌性和雄性小鼠。我们将用高脂饮食治疗APOE 3和APOE 4小鼠， 二甲双胍（糖尿病治疗）或4F肽（促进高密度脂蛋白）。我们将测试我们的 安全的抗炎药物可以减少神经炎症通路的假设 与AD风险因素一致。这些研究将完善目标1中确定的途径， 研究结果通过解决这些治疗是否有功能性CNS后果，通过行为 测定。此外，我们将测试在CNS中鉴定的任何炎症途径是否与在中枢神经系统中的作用相关。 用血浆样本化验血液。在这项R21研究结束时，我们将确定一个子集， 神经炎性分子可以作为AD风险的早期标志物，并确定是否抗- 炎症的方法将是有用的个性化医疗方法，采取APOE基因型，饮食， 考虑到性别。

PROJECT SUMMARY We have previously pursued the hypothesis that APOE genotype alters normal brain neurochemistry and structure early in life, generating an environment that alters the risk of Alzheimer’s Disease (AD) with aging. Studies with APOE knock-in mice have demonstrated that APOE genotype affects neuroinflammation in response to various neurological injuries in an isoform-specific manner, with apoE4 displaying the least anti- inflammatory activity. Inflammation is also a consequence of several environmental risk factors for AD, such as traumatic brain injury, obesity, and metabolic syndrome. Obesity is the strongest environmental risk factor for AD. With 14% of the US population being APOE4 carriers and 35% of the population suffering from obesity, it is extremely important to understand how these two common AD risk factors synergize. Sex is also a critical variable in the risk of cognitive impairments, with females at significantly higher risk. Thus, the risk of AD depends on a complex set of connections between genetic, environmental, and sex effects. This project aims to analyze these interactions in healthy rodent models, thus providing early disease targets that could be use as markers of AD risk and as targets for disease intervention. Aim 1 will determine robust markers of neuroinflammation in APOE3 and APOE4 male and female mice after experiencing chronic peripheral inflammation induced by diet. We will test our hypothesis that specific neuroinflammatory pathways will be coordinately affected by these three AD risk factors. We have begun to identify neuroinflammatory pathways through non-directed transcript analysis, and we will test the rigor of those findings through qPCR. We will further refine specific neuroinflammatory pathways using immunofluorescence, in situ hybridization analyses, and kinase measures. Finally, we will define inflammatory cell responses by defining the density, morphology, and motility of the microglia using our model of CX3CR1GFP/+ mice on APOE3 and APOE4 knock-in backgrounds. Aim 2 will determine the effects of two safe, anti-inflammatory drugs on CNS inflammation markers in the subgroups of most affected APOE female and male mice. We will treat APOE3 and APOE4 mice on a high fat diet with metformin (a diabetes treatment) or 4F peptide (promoting high density lipoproteins). We will test our hypothesis that safe anti-inflammatory drugs could reduce the neuroinflammatory pathways most consistent with AD risk factors. These studies will refine the pathways identified in Aim 1, and further those findings by addressing whether there are functional CNS consequences of these treatments through behavioral assays. Furthermore, we will test whether any inflammation pathways identified in CNS correlate with effects in the blood using assays on plasma samples. By the end of this R21 study, we will have identified a subset of neuroinflammatory molecules that could be use as early markers of AD risk and defined whether anti- inflammatory approaches will be useful in personalized medicine approaches taking APOE genotype, diet, and sex into account.